Automatic circuit breakers



g- 1958 P. M. CHRISTENSEN 2, 8

AUTOMATIC CIRCUIT BREAKERS Origipal Filed April 17, 1951 INVENTOR. P40444. one/.rravsav ,circuit breaker mechanism operated thereby.

United States Patent AUTOMATIC CIRCUIT BREAKERS Paul M. Christensen,West Orange, N. 1., asslgnor to geetllzral Pacific Electric Company, acorporation of ware Original application April 17, 1951, Serial No.221,420. and this application May 8, 1956, Serial No.

8 Ciaims. (Cl. 200-172) The present invention relates to automaticcircuit breakers and is particularly concerned with that form of circuitbreaker in which the mechanism is contained between a pair of moldedpieces of insulation forming an enclosing-housing. As will be seen thisinvention has particular application to that class of circuit breakersin which a moving contact member is part of a sub-assembly that alsocarries its own current-responsive bimetal-andlatch or actuator.

The present application is a division of accompanying application SerialNo. 221,420, filed April 17, 1951, entitled Automatic Circuit Breakers.An object of the present invention is to provide novel structure formingmechanical transmission between an operating handle and A feature ofthis invention involves the use of multi-part handle whose parts arepivoted to the housing sections, which composite handle furnishessupport for one or more elements of the linkage operated by the handle.The illusice! the terminal member 16 is in the form of a prong of theplug-in type as described in the above mentioned application Serial No.127,433, it will be understood that this is not essential to the present'invention but onthe contrary a difierent type of terminal member can beprovided instead.

The stationary contact 20 is carried by the terminal member 14 in aposition within the casing to be engaged by the movable contact 22carried by the movable contact member 24. Said movable contact member ismounted for pivotal movement between the casing parts 10 and 12 to andfrom the circuit-closed position-illustrated in Fig. 1, in which contact22 engages the stationary contact 20, and to and from the circuit-openposition illustrated in Fig. 2 in which said movable contact 22 is showndisengaged from said stationary contact 20. This movement may beaccomplished manually by the handle 26 which is connected to thechannel-shaped actuator 28 by a U-shaped link 30 which is pivotallyconnected at one end thereof to said handle and at its opposite end tosaid'actuator as will hereinafter be more specifically described. Theactuator .28 is pivotally trative circuit breaker will be seen toinclude a tension spring one end of which is anchored to a pin ofinsulation projecting integrally from one of the handle parts; and anoperating link co-acts with the handle parts in such fashion as toprovide clearance for the spring which is also secured to the handle.

The nature of the invention and further features of novelty will bebetter appreciated from the following detailed description of anillustrative embodiment of this invention that follows. The illustrativecircuit breaker is shown in the accompanying drawings forming part ofthis disclosure.

In the drawings:

Fig. 1 is a side view of a circuit breaker embodying the presentinvention, one of the casing parts being removed for the purpose ofillustration, the circuit breaker mechanism being shown closed;

Fig. 2 is a view similar to Fig. 1 showing the circuit breaker mechanismopen;

Fig. 3 is a sectional view on the line 33 of Fig. 1;

Fig. 4 is a sectional view on the line 4-4 of Fig. 1;

Fig. 5 is an end view of the circuit breaker, both casing parts being inplace; and

Figs. 6 and 7 are sectional views on the lines 66 and 7-7 respectivelyof Fig. 3.

Referring now to the drawings in detail the circuit breaker embodyingthe present invention comprises a two-part insulation casing having thecomplementary molded parts 10 and 12 in which the terminals 14 and 16,and the circuit breaker mechanism are mounted, as described for examplein application Serial No. 127,433, filed November 15, 1949, by Thomas M.Cole, and in application Serial No. 217,162, filed March 23, 1951, by meand Thomas M. Cole. It will be understood that the two casing parts 10and 12 are held together by bolts or other suitable means passingthrough openings 19 in casing part 10 and similar openings in casingpart 12 which register with said opening 18 when the two casing partsare in assembled relation. While as here shown,

mounted on the movable contact member as indicated at 32 and isoperatively connected to the movable contact member 24 for moving thelatter, under the control of the current-responsive latch 34 whichincludes a bimetallic strip 36 and an electromagnetic device 38, 40 bywhich said actuator 28 is releasably latched to the movable contactmember 24 as described in the abovementioned application Serial No.127,433. As described in the application Serial No. 217,162, filed March23,

1951, by me and Thomas M. Cole the pivot for the movable contact membermay include the calibration device which comprises a screw 42 having atapering part 44 and which includes the nut 46. The tapering part 44engage the movable contact member in an opening 48 adjacent to andlaterally in communication with recess 50 in the movable contact memberso that by turning the screw 42 in a clockwise direction, viewing Fig.1, part 24a of the movable contact member may be moved or displaced in acounter-clockwise direction (viewing Figs. 1 and 2) with respect to theother part 24b of the movable contact member to which the latch device34 is secured, whereby to provide the desired degree of overlap of thepart 28a of .the actuator 28, thus to predetermine the amount of flexingof the bimetallic strip 36' in actuator-releasing direction, in responseto load condition, for tripping the circuit breaker. Although in theillustrated embodiment, the pivot and calibration device are found as aunit, this is not an essential feature of the present invention and thepivot and calibration may be separate devices as shown, for example, inthe abovementioned application of Thomas M. Cole, Serial No. 127,433.

It will be understood that as illustrated in Fig. 1 when the handle 26is in the on or circuit-closed position thereof and the actuator 28 islatched to the movable contact member 24 by engagement with the outerend of the bimetallic strip 36, as shown, relative pivotal movementbetween the actuator and the movable contact member is prevented andcontact 22 is in engagement with contact 20. In this position, the link30, which pursuant to the present invention may be a rigid link, and theactuator 28, are in overset toggle condition and that in order for thecircuit breaker to open either automatically, i. e., pursuant to theflexing of the bimetal strip 36 either upon heating thereof by theattraction of member 38 to the armature 40 of the electromagnet, thetoggle must be broken, and this can take place either by movement of thehandle 26 to its circuit-open position (Fig. 2) manually or by releaseof the end 280 of the actuator by the bimetal strip 36, when the circuitbreaker trips upon overload or other predetermined load conditions. Theopening of the circuit breaker when the latch 34 releases the actuator28 is efiected by the spring 52 which is connected at one end thereof tothe handle to the part 54 thereof and at its other end to the movablecontact member as indicated at 56. It will be observed that said springis a tension spring and is connected to the movable contact member so asto bias the latter to circuit-open position and to move the latter tothe saidposition when latch 34 disengages actuator 28. Also it will benoted that said spring is efiective to move the handle 26 to its otf' orcircuit-open position when the circuit breaker is tripped, that is whenthe movable contact member moves to a circuit-open position pursuant tothe release of actuator 28 by latch 34. Further it will be observed thateven though the handle 26 is held in on position, said spring isefiective to open the circuit breaker when the latter is tripped, i. e.,when latch 34 disengages actuator 28.

A feature of the present invention is the provision of the floatingpivot for the movable contact member 24 in conjunction with the spring52 for permitting a limited bodily movement of the movable contactmember and for biasing the movable contact 22 toward the stationarycontact 20, in theciosed-circuit position of said movable contact 24 inorder to provide the proper pressure between said contacts when they areengaged, or to compensate for wear or other inequalities in the variousco operating parts of the circuit breaker. For this purpose, the bearingpart 58 of pivot screw 42 and the portion 69 of the companion nut 46have limited movement in the bearing recesses 62 and 64, respectively,of casing parts 12 and 10, respectively. In this connection it will beobserved that hearing recesses 62 and 64 are elongated for slidableengagement, to a limited extent by the corresponding parts 58 and 60 atthe pivot device in a direction transversely of the pivot axis. It willbe noted that in the closed condition of the circuit breaker asillustrated in Fig. l, in which the movable contact member is restrainedagainst pivotal movement, spring 52, being under tension, biases saidmovable contact member 24 for bodily movement toward the handle 26, thatis in a direction to press movable contact 22 resiliently against thestationary contact 20. In this connection it will be understood furtherthat while spring 52 is thus efiective in this manner to press contact22 against contact 20 it is also potentially efiective to move themovable contact member 24 pivotallyto circuit-opening position theinstant latch 34 operates to disengage or release the actuator 28.

Referring now more specifically to handle 26 and link 30, it will beobserved that said handle 26 is here shown in two parts 66 and 68interlocked with each other, for unitary pivotal movement, by aprojection 70 on part 66 which fits into a recess 72 in part 68. Thepivotal mounting for said handle comprises the cylindrical projections74 and 76 on the handle parts which are joumaled in hearing receses 77and 78 in casing parts and 12, respectively. It will be noted that theinner handle portions 80 v and 82 are spaced from each other inconfronting relation and that the part 54 to which spring 52 isconnected is integral with handle portion 80 and projects into the spacebetween handleportions 80 and 82. Said portions 80and 82 are alsoprovided with internal projections 84 and 86 forming pivotal bearingsfor the arms 88 and 90 of link 30 which connects the handle to theactuator 28. Said link also includes a cross member 92 which connectssaid arms 88 and 90 to each other, and a pivot pin 94 pivotally connectsarms 88 and 90 to the adjacent end 'of actuator 28.

It will be understood that various changes in the details ofconstruction and in the arrangement of parts may be made withoutdeparting from the underlying idea or 4 principles of the presentinvention within the scope of the appended claims.

What is claimed is:

l. A circuit breaker, comprising a casing having complementary parts,circuit breaker mechanism disposed between and supported by said parts,said mechanism including a movable contact member and means including amovable handle for actuating the latter, said casing parts having setsof aligned bearing portions for supporting said movable contact memberand said handle, respectively, said handle being formed in complementaryconfronting parts having portions movably supported by said bearingportions, respectively, of the casing, said handle parts havinginterengaging portions which interconnect the handle parts for jointoperation, said handle parts having spaced confronting portions whichare disposed within the casing, and link means forming a part of saidactuating means connected to said handle in the space between said lastmentioned portions of the handle.

2. A circuit breaker, comprising a casing having complementary parts,circuit breaker mechanism disposed between and supported by said parts,said mechanism including a movable contact member and means including amovable handle for actuating the latter, said casing parts having setsof aligned bearing portions for supporting said movable contact memberand said handle, respectively, said handle being formed in complementaryconfronting parts having portionsmovably supported by said bearingportions, respectively, of the casing, said handle parts havinginterengaging portions which interconnect the handle parts for jointoperation, said movable contact member and said handle being pivotallymovable in said bearings and said actuating means including -a U-shapedlink operatively connected to said movable contact member and pivotallyconnected to said handle, said handle parts having circular bearingelements which are respectively pivotally engaged by the arms of saidU-shaped link for said pivotal connection thereof to the handle.

3. A circuit breaker, comprising a casing having complementary parts,circuit breaker mechanism disposed between and supported by said parts,said mechanism including a movable contact member and means including amovable handle for actuating the latter, said casing parts having setsof aligned bearing portions for supporting said movable contact memberand said handle, respectively, said handle being formed in complementaryconfronting parts having portions movably supported by said bearingportions, .respectively, of the casing, said handle parts havinginter-engaging portions which interconnect the handle parts for jointoperation, said handle parts having spaced confronting portions whichare disposed within the casing, and a spring forming part of saidactuating means connected to said movable contact member and to saidlast mentioned handle portions in the space therebetween.

4. A circuit breaker, plementary parts, circuit breaker mechanismdisposed between and supported by said parts, said mechanism including amovable contact member and menu including a movable handle for actuatingthe latter, said casmg parts having sets of aligned bearing portions forsupporting said movable contact member and said handle, respectively,said handle being formed in complementary confronting parts havingportions movably by said bearing portions, said handle parts havinginter-engaging portions which interconnect the handle parts for jointoperation, said handle parts having spaced confronting portions whichare disposed within the casing, said movable contact member and saidhandle being pivotally movable in said bearings and said actuating meansincluding a U-shaped link operatively connected to said movable contactmember and pivotally connected to said handle, said handle parts havingcircular bearing elements which are respectively pivotally engaged bythe arms of said U-shaped comprising a casing having com- 0 supportedrespectively, otthe casing,

' link for said pivotal connection thereof to the handle,

and a spring forming part of said actuating means connected to saidmovable contact member and to said iast mentioned handle portions in thespace therebetween.

5. A circuit breaker, comprising a casing having complementary parts,circuit breaker mechanism disposed between and supported by said parts,said mechanism including a movable contact member and means including amovable handle for actuating the latter, said casing parts having setsof aligned bearing portions for supporting said movable contact memberand said handle, respectively, said handle being formed in complementaryconfronting parts having portions movably supported by said bearingportions, respectively, of the casing, said handle parts havinginterengaging portions which interconnect the handle parts for jointoperation, said handle parts having spaced confronting portions whichparts having sets of aligned bearing portions for supporting saidmovable contact member and said handle, respectively, said handle beingformed in complementary confronting parts having portions movablysupported by said bearing portions, respectively, of the casing, saidhandle parts having interengaging portions which interconnect the handleparts for joint operation, said handle parts haviing spaced confrontingportions which are disposed within the casing, and a spring forming partof said actuating means connected to said movable contact member and tosaid last mentioned handle portions in the space therebetween, saidbearing portions for said movable contact member comprising integralbearing recesses in said casing and constituting a floating mounting forsaid movable contact member, said spring being operable in conjunctionwith said floating mounting for exerting contact pressure in thecircuit-making condition of said mechanism.

7. A circuit breaker including a two-part housing of molded insulationhaving internal part-locating formations, a pair of separable contactsin said housing, mechanism in said housing to open and close saidcontacts, said mechanism including overload responsive means for causingautomatic opening of the contacts and manually operable elements foropening and closing said contacts, said elements including a two-partassembly having a manual lever extending externally of the housing andhaving coaxial bearings mating with complementary internal housingformations, said two-part assembly being axially separable along thebearing axis thereof when the insulation housing is open and saidtwo-part housing being efiective to retain said two-part assemblytogether when the two-part housing is closed, said two-part assemblyconstituting a portion of said mechanism.

8. A circuit breaker, comprising a casing having complementary parts,circuit breaker mechanism disposed between and supported by said parts,said mechanism including a movable contact member and means including amovable handle for actuating the latter, said casing parts having a setof aligned bearing portions for supporting said handle, said handlebeing formed in complementary confronting parts having portions movablysupported by said bearing portions, respectively, of the casing, saidhandle parts reacting against each other for maintaining assemblythereof in said bearings, and said handle having operative connection tosaid movable contact member for actuating the latter.

References Cited in the file of this patent UNITED STATES PATENTS2,050,698 Gaynor Aug. 11, 1936

